The 2013 Arkansas peanut crop is on track to have the highest yield and grade since peanut production returned to the state in 2010. Last year was a very good year for peanut production with an average yield of 4,500 lb/A and grade of 73. Though 40% of the runner peanut crop has yet to be harvested, there are a few reports of 6,000+ lb/A yield with grades of 79+. To date, these are exceptional yield and grade values and the highest reported in Arkansas. This year’s runner peanut crop could average 5,300+ lb/ac and grade 75+. Spanish peanut harvest has averaged ~4,000 lb/A and graded in low 70’s, which are very good numbers for Spanish peanut. Another week of favorable dry weather would benefit growers to finish the 2013 peanut harvest.

Fig. 1 – Inverted runner peanut recently dug by a peanut digger.

To put Arkansas’ exceptional grades in perspective for those who are not familiar with the process, all peanuts are graded after harvest, which is an overall quality and commercial value of a peanut lot. Furthermore and maybe more importantly, a higher grade can mean premium money for the producer. Peanuts are graded by a USDA inspector at all buying points after the peanut kernels are cured or dried in the pod. A 3.3 to 4.4 lb subsample is collected from the trailer with a probe and graded based on several parameters. First, the subsample is graded on the amount of foreign material (rocks, sticks, soil, insect pieces…) and proportion of loose shelled kernels or LSK (kernels out of the pod, Fig. 2), which have a negative value on the grade. A high number of LSK can be an indication that thrashing equipment was improperly set at harvest. Then the sample is shelled and sized. The sound mature kernels (SMK) are intact and undamaged kernels, which have the largest positive effect on the overall grade of a subsample. Broken or split kernels are classified as sound splits (SS, undamaged split kernels) or other kernels (OK), which are worth less than the SMK. As long as the subsamples have less than 4% SS and OK, there is no penalty for the split kernels. Damaged kernels (DK) contain decayed, molded, or discolored skins or testa that can become rancid and moldy when stored, so DK have a negative value on the overall grade. Finally, samples are tested for aflatoxin contamination and those exceeding the 15 ppb (lower threshold than set by USDA on food products of 20 ppb) are crushed for oil or blanched (skins removed and individually inspected for damaged kernels). Aflatoxoin contamination has not been an issue in Arkansas because the crop is 100% irrigated. The overall grade reflects the quality of the crop and efficiency of machinery used at harvest. Typically, a grade greater than 73 is very good and above 78 is exceptional. Growers should use the dried weight and grade when determining final yield weight.

Fig. 2 – A subsample of peanut pods with loose shelled kernels (blue arrow) recently harvested from a peanut field in Arkansas.